This invention relates to processing an image.
Pictures displayed on computer screens are made up of a very large number of closely packed dots known as pixels. Although a color or black-and-white image may include many different colors or shades of gray, each individual pixel displays only a single color or a single shade of gray. A computer accesses data to determine how to light up each pixel in an image. For example, the data may be a single number corresponding to a shade of gray, or a collection of numbers that instruct the computer to light a given pixel by mixing different amounts of red, green, and blue.
An image the size of a small computer monitor requires data for nearly half-a-million pixels. The large amount of data needed to describe each pixel in an image can consume a lot of space on a computer hard disk or take a long time to download over a network. Thus, it would be advantageous to develop a technique for reducing the amount of data needed to represent an image.